Incremental diagnostic value of serum progesterone combined with transvaginal ultrasound in differentiating early ectopic pregnancy: a single-center real-world study
- 1Department of Ultrasound, Wuhu Fanchang District People’s Hospital , ,
Abstract
Objective: To evaluate serum progesterone combined with transvaginal ultrasound for distinguishing ectopic pregnancy (EP) in patients with pregnancy of unknown location (PUL), and to assess diagnostic efficacy across risk stratifications.
Methods: Internally unvalidated analysis included 148 PUL patients (January 2022–December 2025). Final diagnosis by surgical pathology or follow-up divided patients into EP (49) and non-EP (99; intrauterine pregnancy or natural regression). All underwent initial transvaginal ultrasound to confirm PUL. The prediction point was the 48-hour reassessment. Predictors were abnormal adnexal findings on follow-up ultrasound at 48 h, serum progesterone, and 48-hour β-hCG results available at that visit. The intended application is risk re-stratification and follow-up planning at 48-hour reassessment, not replacement of surgical/histopathological diagnosis or immediate treatment. Progesterone and β-hCG were measured; groups were compared. Logistic regression screened independent predictors. ROC curves evaluated single and combined indicators. We assessed if progesterone improved the ultrasound + M6NP model, with M6NP defined as M6 excluding initial progesterone.
Results: The EP group had lower serum progesterone, initial β-hCG, 48-hour β-hCG change rate, and endometrial thickness, and higher abnormal adnexal ultrasound detection (P < 0.05). Multivariate analysis showed log progesterone, abnormal adnexal ultrasound, previous EP, and M6NP high-risk classification (≥5%) were independent predictors (P < 0.05). All AUC values are apparent/in-sample estimates. Ultrasound + M6NP had an apparent AUC of 0.913; adding progesterone increased it to 0.947. In the M6NP high-risk subgroup, progesterone plus ultrasound had an apparent AUC of 0.945 and specificity of 91.67%. Because the model was developed and evaluated in the same dataset without bootstrap or internal validation, estimates are preliminary and require external validation.
Conclusion: Internally unvalidated analysis, serum progesterone combined with transvaginal ultrasound was associated with improved apparent diagnostic accuracy for EP in PUL, especially within M6NP risk stratification. These estimates are apparent/in-sample, preliminary, and hypothesis-generating.
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BibTeX
@article{liu2026incremental,
title = {{Incremental diagnostic value of serum progesterone combined with transvaginal ultrasound in differentiating early ectopic pregnancy: a single-center real-world study}},
author = {Leilei Liu and Yao Cai and Tingting Wang},
journal = {Frontiers in medicine},
year = {2026},
month = oct,
doi = {10.3389/fmed.2026.1949190},
url = {https://europepmc.org/article/PMC/PMC13719595},
note = {CC BY},
}
RIS
TY - JOUR
TI - Incremental diagnostic value of serum progesterone combined with transvaginal ultrasound in differentiating early ectopic pregnancy: a single-center real-world study
AU - Leilei Liu
AU - Yao Cai
AU - Tingting Wang
PY - 2026
DA - 2026/10/16
JO - Frontiers in medicine
DO - 10.3389/fmed.2026.1949190
UR - https://europepmc.org/article/PMC/PMC13719595
AB - Objective: To evaluate serum progesterone combined with transvaginal ultrasound for distinguishing ectopic pregnancy (EP) in patients with pregnancy of unknown location (PUL), and to assess diagnostic efficacy across risk stratifications. Methods: Internally unvalidated analysis included 148 PUL patients (January 2022–December 2025). Final diagnosis by surgical pathology or follow-up divided patients into EP (49) and non-EP (99; intrauterine pregnancy or natural regression). All underwent initial transvaginal ultrasound to confirm PUL. The prediction point was the 48-hour reassessment. Predictors were abnormal adnexal findings on follow-up ultrasound at 48 h, serum progesterone, and 48-hour β-hCG results available at that visit. The intended application is risk re-stratification and follow-up planning at 48-hour reassessment, not replacement of surgical/histopathological diagnosis or immediate treatment. Progesterone and β-hCG were measured; groups were compared. Logistic regression screened independent predictors. ROC curves evaluated single and combined indicators. We assessed if progesterone improved the ultrasound + M6NP model, with M6NP defined as M6 excluding initial progesterone. Results: The EP group had lower serum progesterone, initial β-hCG, 48-hour β-hCG change rate, and endometrial thickness, and higher abnormal adnexal ultrasound detection (P < 0.05). Multivariate analysis showed log progesterone, abnormal adnexal ultrasound, previous EP, and M6NP high-risk classification (≥5%) were independent predictors (P < 0.05). All AUC values are apparent/in-sample estimates. Ultrasound + M6NP had an apparent AUC of 0.913; adding progesterone increased it to 0.947. In the M6NP high-risk subgroup, progesterone plus ultrasound had an apparent AUC of 0.945 and specificity of 91.67%. Because the model was developed and evaluated in the same dataset without bootstrap or internal validation, estimates are preliminary and require external validation. Conclusion: Internally unvalidated analysis, serum progesterone combined with transvaginal ultrasound was associated with improved apparent diagnostic accuracy for EP in PUL, especially within M6NP risk stratification. These estimates are apparent/in-sample, preliminary, and hypothesis-generating.
SN - 2296-858X
ER -